It is well known in the art to provide a door hardware assembly that is operable to maintain a door in a closed position by selectively securing the door to a doorframe. It is equally well known to provide a door hardware assembly that is capable of being locked to selectively prevent operation of the door hardware assembly. As can be appreciated, by preventing operation of the door hardware assembly, the door will remain closed and in a locked condition. Such conventional door hardware assemblies generally include a handle assembly, lock cylinder, and key, whereby the key is operable to selectively lock the lock cylinder to prevent operation of the door handle assembly and maintain the door in the closed and locked condition.
Conventional door hardware assemblies are typically disposed on a door proximate to an edge of the door for selective engagement with a striker assembly mounted on a door frame. As previously discussed, door hardware assemblies commonly include a handle assembly, lock cylinder, and key. The lock cylinder is designed to matingly receive a key, whereby the key is operable to toggle the lock cylinder between a locked and unlocked condition. The unlocked condition of the lock cylinder permits rotation of the handle assembly and, thus, movement of the door relative the doorframe. The locked condition prohibits rotation of the handle assembly, thereby maintaining the door in a closed and locked condition. As can be appreciated, the key is specific to the particular lock cylinder so as to prevent unwanted operation of the door handle assembly and movement of the door relative the doorframe. In this regard, a lost or stolen key may provide unwanted operation of the lock cylinder and unwanted access through the door. For at least this reason, being able to “reset” or “re-key” the lock cylinder, without having to replace the entire mechanism, is a desirable feature. In this regard, conventional door hardware assemblies commonly provide for adjustment of a locking mechanism disposed within the lock cylinder.
Re-keying of a conventional lock cylinder provides the lock cylinder with a new key that is operable to lock and unlock the re-configured lock cylinder, while concurrently prohibiting further use of the lost key. Such lock cylinders commonly include a plurality of pin assemblies, whereby each pin assembly includes an upper pin slidably disposed within an upper shear cylinder and a lower pin slidably disposed within a lower shear cylinder. The upper and lower shear cylinders are axially aligned such that a first shear zone is formed between the upper and lower pins and a second shear zone is formed between the upper and lower shear cylinders. As previously discussed, a key is used to selectively lock and unlock the lock cylinder, whereby raised portions disposed on the key are operable to engage the upper and lower pins to properly align the second shear zone with the first shear zone. Proper alignment of the first and second shear zones allows each pin to disengage the respective shear cylinder and permit rotation of the door handle assembly.
In a re-keying operation, the upper and lower pins are adjusted to vary the relative heights of each of the upper and lower pins. In this regard, a new key having raised portions commensurate with the new pin heights of each pin assembly, is required to properly align the first and second shear zones of the upper and lower pins. Once the new pins are installed, the lock cylinder will no longer permit rotation of the door handle assembly if the old key is used in the lock cylinder. As can be appreciated, the old key is not commensurate with the new pin heights and therefore will not properly align the first and second shear zones of the respective pin assemblies.
While conventional lock cylinders adequately provide for a re-keying operation of a lock cylinder, they suffer from the disadvantage of requiring partial disassembly of the lock cylinder and typically require a specialized technician, such as a locksmith, to perform the re-keying operation. Further, conventional lock cylinders suffer from the disadvantage of requiring various pin heights and combinations thereof to properly re-key the cylinder. Further yet, conventional re-keying kits require door hardware manufacturers to produce varying pin heights for each kit, thereby overproducing the required number of individual pins to simply re-key one lock cylinder.
Therefore, a lock cylinder that provides for a re-keying operation without requiring disassembly of the lock cylinder is desirable in the industry. Furthermore, a lock cylinder that is capable of being re-keyed without replacing the existing components is also desirable. Further yet, a lock cylinder that provides for a re-keying operation without requiring a plurality of additional pins with varying pin heights is also desirable.